Translation in Backend

Hi. Sorry when i ask again, but I closed my last quesion, because there were various problems in one question.

I still have the problem in backend, that the backend ts not really in german. But the files are translated. For the backend self its not really a problem, but for the workflow. So, all custom fields are in english and I have to translate every event, profile. ....... The work should be unnecessary , because actually everything is already translated from yourside .

What can I do? Thanks.